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High-entropy-alloy catalyst boosts propane dehydrogenation efficiency

High-entropy-alloy catalyst to boost propane dehydrogenation efficiency
Progressive fabrication of HEA/SiO2. (a) Schematic progressive design of the HEA catalyst with abundant isolated Pt sites on the surface by introducing Cu, Sn, Au, and Pd. (b) XRD patterns of HEA/SiO2 and pure SiO2. (c) HAADF-STEM image and corresponding size distribution of HEA/SiO2. (d) Elemental mapping for nanoparticles of HEA/SiO2. Credit: Prof. Zeng鈥檚 team

A research team from the University of Science and Technology of China (USTC) of the Chinese Academy of Sciences has recently developed a Pt-based high-entropy-alloy (HEA) catalyst that significantly enhances the efficiency of propane dehydrogenation (PDH), a critical process for producing propylene, which is a major chemical building block. The study was in Angewandte Chemie International Edition.

Propane dehydrogenation is an essential route for propylene production, which is a key feedstock in the chemical industry. However, the process requires high temperatures that often lead to deactivation due to sintering and coke formation.

Traditional Pt-based catalysts, while effective, can promote side reactions, reducing selectivity and stability. The quest for a catalyst that can withstand these and maintain has been a significant challenge in the field.

Therefore, (HEAs), composed of five or more principal metals in a solid solution, have emerged as a potential solution due to their broad compositional space and adaptable electronic states. However, the exploration of HEA catalysts has been dominated by time-consuming and labor-intensive trial-and-error approaches, highlighting the need for a more rational design strategy.

To address the time-consuming challenge, the research team employed a fast-moving tube furnace for catalyst preparation to synthesize HEA nanoparticles with a uniform and stable structure. Metal precursors were loaded onto a fumed silica support and then rapidly reduced in the preheated furnace.

This fast process, completed within 1 second, bypassed the temperature-rising stage and enabled the simultaneous decomposition and reduction of all precursors, effectively avoiding potential phase separation.

To improve traditional trial-and-error methods, the research team embarked on a progressive approach to design and fabricate HEA catalysts guided by alloying effects. They selected Cu, Sn, Au, and Pd to induce specific effects on Pt, such as dilution, encapsulation, surface enrichment, and inhomogeneity, respectively. This strategic selection and combination of metals allowed them to manipulate the geometric and electronic properties of the catalyst, thereby enhancing its performance in PDH.

By leveraging and balancing these alloying effects, the research team successfully fabricated the PtCuSnAuPd/SiO鈧 HEA catalyst. This catalyst demonstrated outstanding catalytic performance in PDH.

At a weight hourly space velocity (WHSV) of 354 h鈦宦, it achieved propylene formation rates of 256 and 390 mol C鈧僅鈧 g鈧氣倻鈦宦 h鈦宦 at 550掳C and 600掳C, respectively, significantly outperforming many other reported multimetallic alloys. The catalyst also exhibited high selectivity for propylene, with selectivity remaining above 97% in a 220-hour long-term stability test.

The novel catalyst offers a combination of high activity, selectivity, and stability, which could have a significant impact on the production of propylene in the chemical industry. The rational design strategy based on understanding alloying effects provides a new approach for the development of advanced catalysts for other reactions as well.

More information: Jun Luo et al, Progressive Fabrication of a Pt鈥怋ased High鈥怑ntropy鈥怉lloy Catalyst toward Highly Efficient Propane Dehydrogenation, Angewandte Chemie International Edition (2024).

Citation: High-entropy-alloy catalyst boosts propane dehydrogenation efficiency (2024, November 26) retrieved 8 June 2025 from /news/2024-11-high-entropy-alloy-catalyst-boosts.html
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